Photocurable liquid polyene-polythiol polymer compositions

ABSTRACT

The invention disclosed is for a new photocurable liquid polymer composition which includes a liquid polyene component having a molecule containing at least two unsaturated carbon-to-carbon bonds disposed at terminal positions on a main chain of the molecule, a polythiol component having a molecule containing a multiplicity of pendant or terminally positioned -SH functional groups per average molecule, and a photocuring rate accelerator. The photocurable liquid polymer composition upon curing in the presence of actinic light forms odorless, solid, elastomeric or resinous products which may serve as sealants, coatings, adhesives and molded articles.

United States Patent 1 51 3,661 ,744 Kehr et al. May 9, 1972 [54] PHOTOCURABLE LIQUID POLYENE- [56] References Cited POLYTHIOL POLYNIER UNITED STATES PATENTS COMPOSITIONS 3,405,181 10 1968 Gourdon 260 79 [72] Inventors: Clifton L. Kehr, Silver Sprmg; Walter R. 3 278 352 102966 Erickson 260179 sykesvne bmh 3,371,072 2/1968 Signouret et al.. ..260/79 [73] Assignee: W. R. Grace & Co., New York, NY, 3,338,810 8/1967 Warner... ..260/79 3,412,049 11/1968 Gmitter 260/2.5 R [221 Flledl June 1970 2,921,006 1/1960 Schmitz et al. ..204/159 15 21 Appl. No.2 44,607 I Primary Examiner-Murray Tillman Related U.S. Application Data Assistant ExaminerRichard B. Turer [63] Continuation-impart of Ser. No. 617,801, Feb. 23, may-Eugene and Kenneh 1967, abandoned, which is a continuation-in-part of Ser. NO. 567,841, July 26, 1966, abandoned. [57] ABSTRACT The invention disclosed is for a new photocurable liquid [52] U.S. C1 ..204/159.14, 1 17/9331, 1 17/132 B, polymer composition which includes a ]iquid polyene com- 1 1 32 1338 1 ponent having a molecule containing at least two unsaturated carbon-to-carbon bonds disposed at terminal positions on a 2 R, 260/41 main chain of the molecule, a polythiol component having a 2 /41 2 R, 260/41 26O/63 molecule containing a multiplicity of pendant or terminally 2 2 positioned SH functional groups per average molecule, and a photocuring rate accelerator. The photocurable liquid 260/858, 260/37 olymer composition upon curing in the presence of actinic [51 Int. C1 1/16, C080 1 li ht f rm odorle s olid elastomeric or resinous p gducts [58] Field of Search ..260/77.5 MA, 77.5 AM, 79.7, which may serve as sealants, coatings, adhesives and molded 260/79.5 B, 79.5 R, 79.5 CR; 204/159.18, 159.23, ni l 31 Claims, No Drawings PHOTOCURABLE LIQUID POLYENE-POLYTHIOL POLYMER COMPOSITIONS The present application for U.S. Letters Patent is a continuation-in-part of copending application Ser. No. 617,801, filed Feb. 23, 1967, and now abandoned, which in turn is a continuation-in-part of application Ser. No. 567,841, filed July 26, 1966, now abandoned.

This invention relates to a new photocurable liquid composition which includes a liquid polyene component having a molecule containing at least two unsaturated carbon-to-carbon bonds disposed at terminal positions on a main chain of the molecule, a polythiol component having a molecule containing a multiplicity of pendant or terminally positioned SH functional groups per average molecule, and a photocuring rate accelerator.

It is well known in the art that cure of internally unsaturated polymers such as polybutadiene or polyisoprene may be effected with polythiols. However, such polymers, due mainly to residual internal unsaturation after curing, are unstable either to thermal oxidation or ultra-violet catalyzed oxidation, and are subject to rapid attack by ozone. Eventually degradation and embrittlement results in the internal double bond polymers, substantially reducing their useful service life.

A limitation of commercially available liquid polyurethane prepolymers is the fact that they are terminated by isocyanate (NCO) groups. These NCO groups are extremely unstable in storage, and are highly water-sensitive such that under practical conditions, they react with traces of moisture from the atmosphere to form gaseous carbon dioxide and amino groupings which in turn react with more NCO to form eventually a highly viscous, sometimes completely insoluble ureaextended chain network. In cases where insolubilization occurs, the polymer has to be discarded at great expense. Further, if the NCO-terminated prepolymers come in contact with traces of either acidic or basic impurities, dimerization and/or trimerization of the NCO functions may take place to form viscous, sometimes insoluble products during storage. Even mild alkalis such as those constituents normally present on the surface of glass vessels and containers may cause storage problems.

A further limitation for some applications is found in polyu rethane polymers of the prior art which are derived from aromatic diisocyanates or pdlyisocyanates such as tolylene-2,4- diisocyanate, tolylene-2,fi-diisocyanate, 4,4-diisocyanatodiphenylmethane', and the like. These aromatic diisocyanates (or mixtures thereof) enjoy widespread use in polyurethane elastomers, foams, and coatings, because of their ready commercial availability, high degree of reactivity and relatively low cost. The derived polyurethane products, however, are known to turn yellow, amber, orange or brown in color when exposed to sunlight, ultraviolet light or other forms of actinic radiation. This yellowing tendency imparts a definite limitation on the usage of such polyurethanes in many applications. There is evidence in the technical literature that shows that this yellowing or discoloration problem is directly attributable to the aromatic (benzeneoid) nucleus in the aromatic diisocyanates, and accordingly serious yellowing problems in polyurethanes may be avoided by use of aliphatic polyisocyanates such as hexamethylene diisocyanate. These aliphatic polyisocyanates, however, are difficult to manufacture, are relatively expensive and are relatively slow in reaction rate during polymer formation reactions in comparison to the aromatic polyisocyanates.

The use of polymeric liquid polythiol polymers which are cured to solid elastomeric products by oxidative coupling of the thiol (-SH) groups to disulfides (-SSgroups) are known in the sealants, coatings and adhesives field. Oxidizing agents such as PbO are commonly used to effect this curing reaction. These mercapto-containing compounds, however, both before and after curing with Pbo -type curing system yield elastomeric compositions with an offensive odor which limits their usefulness generally to outdoor service. Thus, oxidatively-cured mercapto polymer systems have found restricted commercial acceptance due to their offensive odors. Y

A limitation of commercial liquid polymeric sealants and coatings is found in one-package systems. All the compound- In these commercial sealants (polysulfides, polydisulfides, polymercaptans, polyurethanes and polysilicones), the curing reaction of one-package systems is initiated by moisture (H O) from the air. The moisture-curable systems leave something to be desired because the moisture content of the air varies widely. Hence, the curing performance of moisturecurable adhesives, coatings and sealants is variable and is difficult to predict and control. In the case of polyurethanes a further disadvantage of moisture-curable systems is observed. in the curing reaction (NCO groups reacting with H O) a volatile gas (carbon dioxide) is liberated and this evolved gas tends to cause unsightly and property-weakening gas pockets or voids in the final product.

It has now been found that numerous defects of the prior art may be effectively overcome by practice of the present invention which provides a new photocurable liquid composition containing particular polyenes which are curable by polythiols to solid resins or elastomers. For example, when urethanecontaining polyenes are compounded with polythiols, the prepared composition may be stored safely for long periods of time in the absence of actinic light. Upon exposure of actinic light such as ultraviolet light, the prepared system may be cured rapidly and controllably to a polythioether-polyurethane product which is low in cost and equal or better in reaction rate in polymer formation when compared with compositions derived from conventional technology.

Generally stated, the present invention provides a photocurable composition which comprises a particular polyene component, a polythiol component, and a photocuring rate accelerator.

The polyene component may be represented by the formuwherein m is an integer of at least 2, wherein X is a member selected from the group consisting of:

In the groups (a) to (e),f is an integer from 1 to 9; R is a radical selected from the group consisting of hydrogen, fluorine, chlorine, furyl, thienyl, pyridyl, phenyl and substituted phenyl, benzyl and substituted benzyl', alkyl and substituted alkyl, alkoxy and substitutedalkoxy, and cycloalkyl and substituted cycloalkyl. The substituents on the substituted members are selected from the group consisting of nitro, chloro, fluoro, acetoxy, acetamide, phenyl, benzyl, alkyl, alkoxy and cycloalkyl. Alkyl and alkoxy have from one to nine carbon atoms and cycloalkyl has from three to eight carbon atoms.

The members (a) to (e) are connected to [A] through divalent chemically compatible derivative members. The

members (a) to (e) may be connected to [A] through a divalent chemically compatible derivative member of the group consisting of Si(R),, carbonate, carboxylate, sulfone,

and consisting of atoms selected from the group consisting of 20 carbon, oxygen, nitrogen, chlorine, bromine, fluorine, phosphorus, silicon and hydrogen.

The polyene component has a molecular weight in the range from about 64 to 20,000, preferably about 200 to about 10,000; and a viscosity in the range from essentially to 20 million centipoises at 70 C. as measured by a Brookfield Viscometer.

The polythiol component has a molecular weight in the range from about 50 to about 20,000 and the general formula:

wherein R is a polyvalent organic moiety free from reactive carbon-to-carbon unsaturation and n is at least 2. The polyene/polythiol mole ratio are selected so as to provide a solid, self-supporting cured product under ambient conditions in the presence of actinic light.

More particularly, the member [A] of the polyene composition may be formed primarily of alkyl radicals, phenyl and urethane derivatives, oxygenated radicals, and nitrogen substituted radicals. The member [A] may also be represented by wherein j and k are integers greater than 1; R is a member of the group consisting of hydrogen, and alkyl having one to nine carbon atoms; R, is a member of the group consisting of hydrogen, and saturated alkyl having one to nine carbon atoms; R, is a divalent derivative of the group consisting of phenyl, benzyl, alkyl, cycloalkyl, substituted phenyl, substituted benzyl, substituted alkyl and substituted cycloalkyl; with the terms alkyl, cycloalkyl and members substituted being defined above.

General representative formulas for the polyenes of the present invention may be prepared as exemplified below:

I. Poly (alkylene-ether) Polyol Reacted with Unsaturated Monoisocyanates Forming Polyurethane Polyenes and Related Polymers Interconnvct\d-Modifiod Tclmfuuctionul 11. Poly (aJkylene-ester) Polyol Reacted with Unsaturated Monoissocyanates Forming Polyurethane Polyenes and Related Ill. Poly (alkylene-ether) Polyol Reacted with Polyisocyanate and Unsaturated Monoalcohol Forming Polyurethane Polyenes 'Ietralunctional in the above formulas, the sum of x y z in each chain segment is atleast 1; P is an integer of l or more; q is at least 2; n is at least 1; R, is selected from the group consisting of hydrogen, phenyl, benzyl, alkyl, cycloalkyl, and substituted phenyl; and R is a member of the group consisting of v CH,=Cl-l Cl-i, hydrogen, phenyl, cycloalkyl, and alkyl.

The novel class of polyenes of this invention derived from carbon to carbon unsaturated monoisocyanates may be characterized by extreme ease and versatility of manufacture when the liquid functionality desired is greater than about three. For example, consider an attempted synthesis of a polyhexene starting with an OH terminated polyalkylene ether hexol such as Niax Hexol LS-490 (Union Carbide Corp.) having a molecular weight of approximately 700, and a viscosity of 18,720 cps at 20 C. An attempt to terminate this polymer with e'ne groups by reacting 1 mole of hexol with 6 moles of tolylene diisocyanate (mixed-2,4-, -2-6- isomer product) and-6 moles of allyl alcohol proceeded nicely but" resulted in a prematurely chain extended and crosslinked solid product rather than an intended liquid polyhexene. Using the monoisocyanate route, however, this premature chain extension may be avoided and the desired polyurethane-containing liquid polyenes from other analagous highly functional polyols vsuch as cellulose, polyvinyl alcohol, partially hydrolized 'polyvinyl acetate, and the like, and highly functional 1 polyamines such as tetraethylene pentamine,

polyethyleneimine, and the like.

A general method of forming one type of polyene containing urethane groups is to react a polyol of the general formula Rr1 ('OH),, wherein R is a polyvalent organic moiety free from reactive carbon-to-carbon unsaturation and n is at least 2; with a polyisocyanate of the general formula R,=(-NCO),

wherein R 'is a polyvalent organic moiety free from reactive carbon-to carbon unsaturation and n is at least 2 and a f member of the group consisting of anene-ol, yne -ol, ene-- amine and yneamine. The reaction is carried out in an inert moisture-free atmosphere (nitrogen blanket) at atmospheric pressure at a temperature in the range from" 0 to about 120 C for a period of about 5 minutes to about 25 hours. In the case where an ene-ol or yne-ol is employed, the reaction is preferably a one step reaction wherein all the reactants are charged together. In the case where an ene-amine or yneamine is used, the reaction is preferably a two step reaction wherein the polyol and the polyisocyanate are reacted together and thereafter preferably at room temperature, the ene-amine or yne-amine is added to the NCO terminated polymer formed. The group consisting of ene-oi, yne-ol, eneamine and yneamine are usually added to the reaction in an amount such that there is one carbon-to-carbon unsaturation in the group member per hydroxyl group in the polyol and said polyol and group member are added in combination in a stoichiometric amount necessary to react with the isocyanate groups in the polyisocyanate.

, A second general method of forming a polyene containing .urethane groups (or urea groups) is'to react a polyol (or polyamine) with an ene-isocyanate or an yne-isocyanate to form the corresponding polyene. The general procedure and stoichiometry of this synthesis route is similar to {that described for polyisocyanates in the preceding. In this instance, a polyol reacts with an ene-isocyanate to form the corresponding polyene. It is found, however, that products derived from this route, when cured in the presence of an ac- These polar functional groupings serve as connecting linkages between multiple repeating units in the main chain series, and serve as internal strength-reinforcing agents by virtueof their ability to create strong interchain attractionforces between molecules of polymer in the final cured composition.

Polyenes containing ester groups may be formed by reacting an acid of the formula R,,-(-COOH),, wherein R is a polyvalent organic moiety free from reactive carbon-to-carbon unsaturation and n is at least2; with either an ene-ol or yne-ol. The reaction is carried out in an inert moisture-free armosphere (nitrogen blanket) at atmospheric pressure at a temperature in the range from 0 to about 120 C. for a period of 5 minutes to 25 hours. Usually the reaction iscarried out in the presence of a catalyst (p-toluene sulfonic acid) and in the presence of a solvent, e.g., benzene at refluxing temperature. The water formed is azeotroped off of the reaction.

Another method of making an'estercontaining polyene is to react a polyol of the formula R (-OH)n wherein R is a polyvalent organic moiety free from reactive carbon-to-carbon unsaturation and n is at least 2; with either an ene-acid or an yne-acid. The reaction is carried out in the same manneras set out above for the ester-containing polyenes. ln practicing this latter technique, however, it may be found that ene-acids (or yne-acids) in which the ene (or yne) group is adjacent to an activating polar moiety such as and the like are generally not desirable within the scope of this invention. These activated ene compounds are very prone speed up the reaction. This is especially true in the case where .an ene-ol is used to form the polyene. Such ca'talysts are well :known to those in the art and include organometallic com- :pounds such as stannous octoate, stannous oleate, dibutyl tin tive light source and a polythiol, may form relatively weak solid 'polythioether products. To obtain stronger cured products, it is desirable to provide polar functional groupings two or more reactive unsaturated carbon-to-carbon bonds located terminal from the main chain with a polythiol containing two or more thiol groups per molecule and thereafter exposing said liquid mixture having photocuring rate accelerator to actinic light, there is provided an essentially odorless solid elastomeric or resinous polymeric product.

Polythiol as used herein refers to simple or complex organic compounds having a multiplicity of pendant or terminally positioned -SH functional groups per average molecule.

On the average the polythiol must contain two or more SH groups/molecule and have a viscosity range of essentially 0 to 20 million centipoises (cps) at 70 C as measured by a Brooktreld viscometer either alone or when in the presence of an inert solvent, aqueous dispersion or plasticizer. Operable polythiols in the instant invention usually have molecular weights in the range about 50 to about 20,000,.and preferably from about to about 10,000. v v

The polythiols operable in the instant invention may be exemplified by the general formula R. (S H),, where n is at least 2 and R, is a polyvalent organic moiety free from reactive carbon-to-carbon unsaturation. Thus R, may contain cyclic groupings and hetero atoms such as N, P or O and primarily contains carbon-carbon, carbon-hydrogen, carbon-oxygen, or silicon-oxygen containing chain linkages free of any reactive carbon-to-carbon unsaturation.

One class of polythiols operable with polyenes to obtain essentially odorless polythioether products are esters of thiolcontaining acids of the formula HSR COOH where R is an organic moiety containing no reactive carbon-to-carbon unsaturation with polyhydroxy compounds of structure R H),, where R is an organic moiety containing no reactive carbon-to-carbon unsaturation, and n is 2 or greater. These components will react under suitable conditions to give a polythiol having the general structure:

where R and R are organic moieties containing no reactive carbon-to-carbon unsaturation, and n is 2 or greater.

Certain polythiols such as the aliphatic monomeric polythiols (ethane dithiol, hexamethylene dithiol, decamethylene dithiol, tolylene-2,4-dithiol, and the like, and some polymeric polythiols such as a thiol-terminated ethylcyclohexyl dimercaptan polymer, and the like, and similar polythiols which are conveniently and ordinarily synthesized on a commercial basis, although having obnoxious odors, are operable but many of the end products are not widely accepted from a practical, commercial point of view. Examples of the polythiol compounds preferred because of relatively low odor level include but are not limited to esters of thiogyl colic acid (HS-CH COOH), a-mercaptopropionic acid (HSCl-l(Cl-l )CO0l-l and B-mercaptopropionic acid (HS-Cl-hClfiCOCl-I) with polyhydroxy compounds such as glycols, triols, tetraols, pentaols, hexaols, and the like. Specific examples of the preferred polythiols include but are not limited to ethylene glycol bis (thioglycolate), ethylene glycol bis (B-mercaptopropionate), trimethylolpropane tris (thioglycolate trimethylolpropane tris ,B-mercaptopropionate), pentaerythritol tetrakis (thioglycolate) and pentaerythritol tetrakis (B-mercaptopropionate), all of which are commercially available. A specific example of a preferred polymeric polythiol is polypropylene ether glycol bis (,B-mercaptopropionate) which is prepared from polypropylene-ether glycol (e.g. Pluracol P201 Wyandotte Chemical Corp.) and ,B-mercaptopropionic acid by esterification.

The preferred polythiol compounds are characterized by a low level of mercaptan-like odor initially, and after reaction, give essentially odorless polythioether end products which are commercially attractive and practically useful resins or elastomers for both indoor and outdoor applications.

Prior to curing, the curable liquid polymer may be formulated for use as 100 percent solids, or disposed in organic solvents, or as dispersions or emulsions in aqueous media.

The curable liquid polymer compositions prior to curing may readily be pumped, poured, siphoned, brushed, sprayed,

doctored, or otherwise handled as desired. Following application, curing in place to a solid resin or elastomer may be effected either very rapidly or extremely slowly as desired by manipulation of the compounding ingredients and the method of curing.

The liquid polythioether-forming components and composi tions, prior to curing, may be admixed with or blended with other monomeric and polymeric materials such as thermoplastic resins, elastomers or thermosetting resin monomeric or polymeric compositions. The resulting blend may be subjected to conditions for curing or co-curing of the various components of the blend to give cured products having unusual physical properties.

Although the mechanism of the curing reaction is not completely understood, it appears most likely that the curing reaction may be initiated by most any actinic light source which disassociates or abstracts a hydrogen atom from an SH group, or accomplishes the equivalent thereof. Generally the rate of the curing reaction may be increased by increasing the temperature of the composition at the time of initiation of cure. In many applications, however, the curing is accomplished conveniently and economically by operating at ordinary room temperature conditions. Thus for use in elastomeric sealants, it is possible merely to photoexpose the polyene, polythiol, photocuring rate accelerator admixture to ambient conditions and obtain a photocured solid elastomeric or resinous product.

By proper choice of type and concentration of photocuring rate accelerator for initiation, the curing period required for conversion of the polyene/polythiol composition from the liquid to the solid state may be varied greatly as desired. In combination with suitable accelerators or retarders, the curing period may vary from about a second or less to about 30 days or more. In general, short curing periods are achieved in applications where thin films of curable composition are required, such as in the field of coatings whereas the long curing periods are achieved and desired where more massive layers of composition are required, such as in the field of elastomeric sealants.

A class of actinic light useful herein is ultraviolet light and other forms of actinic radiation which are normally found in radiation emitted from the sun or from artificial sources such as Type RS Sunlamps, carbon arc lamps, xenon arc lamps, mercury vapor lamps, tungsten halide lamps and the like. Ultraviolet radiation may be used most efficiently if the photocurable polyene/polythiol composition contains a suitable photocuring rate accelerator. Curing periods may be adjusted to be very short and hence commercially economical by proper choice of ultraviolet source, photocuring rate accelerator and concentration thereof, temperature and molecular weight, and reactive group functionality of the polyene and polythiol. Curing periods of less than about 1 second duration are possible, especially in thin film applications such as desired for example in coatings and adhesives.

Conventional curing inhibitors or retarders which may be used in order to stabilize the components or curable compositions so as to prevent premature onset of curing may include hydroquinone; p-tert.-butyl catechol; 2,6-di tert.-butyl-pmethylphenol; phenothiazine; N-phenyl-Z-naphthylamine; inert gas atmospheres such as helium, argon, nitrogen and carbon dioxide; vacuum; and the like.

It is understood to be within the scope of this invention that the photocuring rate accelerator may be present as a separate and distinct component such as azobenzene, as a mixture of two or more separate components, such as benzophenone; benzanthrone; anthrone, and dibenzosuberone; carbon tetrachloride and phenanthrene; and the like, or in a chemically combined form within the molecular structure of either the polyene or the polythiol. An example of this latter condition wherein the photocuring rate accelerator is present not as a separate component, but rather in a form chemically combined within the polyene component is the following structure which contains four reactive carbon-to-carbon unsaturated groupings and one diaryl ketone grouping per average molecule:

It is further understood that the polyene, the polythiol or the photocuring rate accelerator may be formed in situ in the photocurable composition without departing from the spirit of this invention.

Specifically useful herein are chemical photocuring rate accelerators such as benzophenone, acetophenone, acenapthene-quionone, o-methoxy benzophenone, Thioxanthen-9-one, xanthen-9-one, 7-H-Benz[de]anthracen-7-one, diben-zosuberone, l-napththaldehyde, 4,4'-bis (dimethylamino) benzophenone, fluorene-9-one, l-

acetonaphthone, 2'-ace-tonaphthone, anthraquinone, l-indanone, 2-tert.-butyl anthraquinone, valerophenone, hexanophenone, 8-phenyl-butyrophenone, p-mor pholinopropiophenone, 4-morpholino-benzophenone, 4'- morpholinodeoxybenzoin, p-diacetylbenzene, 4- aminobenzophenone, 4'-methoxyacetophenone, benzaldehyde, a-tetralone, Q-acetylphenanthrene, 2- acetylphenanthrene, l-thioxanthenone, 3-

acetylphenanthrene, 3-acetylindole 1,3,5-triacetylbenzene, and the like including blends thereof, to greatly reduce the ex posure times.

The curing rate accelerators are usually added in an amount ranging from about 0.005 to about 50 percent by weight of the photocurable composition, with a preferred range being from about 0.05 to about 25 percent by weight. Preferred photocuring rate accelerators are the aldehyde and ketone carbonyl compounds having at least one aromatic nucleus attached directly to the i group.

To obtain the maximum strength, solvent resistance, creep resistance, heat resistance and freedom from tackiness, the reaction components consisting of the polyenes and polythiols of this invention are formulated in such a manner as to give solid, crosslinked, three dimensional network polythioether polymer systems on curing. In order to achieve such infinite network formation the individual polyenes and polythiols must have a functionality of at least 2 and the sum of the functionalities of the polyene and polythiol components must always be greater than 4. Blends and mixtures of the polyenes and the polythiols containing said functionality are also operable herein.

The compositions to be cured, i.e., (converted to solid resins or elastomers) in accord with the present invention may, if desired, include such additives as antioxidants, accelerators, dyes, inhibitors, activators, fillers, pigments, antistatic agents, flame-retardant agents, thickeners, thixotropic agents, surface-active agents, viscosity modifiers, extending oils, plasticizers, tackifiers and the like within the scope of this invention. Such additives are usually preblended with the polyene or polythiol prior to or during the compounding step. Operable fillers include natural and synthetic resins, carbon black, glass fibers, wood flour, clay, silica, alumina, carbonates, oxides, hydroxides, silicates, glass flakes, glass beads,

- cc. dry benzene was added to the kettle and the reaction FORMATION OF POLYENE PREPOLYMER Example 1 product was azeotroped with benzene to remove the unreacted alcohol. This allyl terminated liquid prepolymer had a molecular weight of approximately 2100 and will be referred to as Prepolymer A hereinafter.

EXAMPLE 2 400 g. (0.2 moles) of Adiprene L-l00" was charged to a dry resin kettle maintained under nitrogen and equipped with a condenser, stirrer, thermometer and gas inlet and outlet.

25.2 g. (0.43 moles) of propargyl alcohol (HC 5 CCH,OH) I was added to the kettle and the reaction was continued with stirring for 18 hours at 160 C. Thereafter the nitrogen atmosphere was removed and the kettle was evactuated 16 hours at 100 C followed by azeotropic distillations with 50 cc. water and then 50 cc. benzene to remove any excess propargyl alcohol. This HC 5 C- terminated liquid prepolymer had a viscosity of 27,500 centipoises at 70 C and a molecular weight of 2100 and will be referred to as Prepolymer B hereinafter.

EXAMPLE 3 1 mole of commercially available poly(ethylene ether) glycol having a molecular weight of 1450 and a specific gravity of 1.21 was .charged to a resin kettle maintained under nitrogen and equipped with a condenser, stirrer, thermometer and a gas inlet and outlet. 2.9 g. dibutyl tin dilaurate as a catalyst was charged to the kettle along with 2 moles tolylene- 2,4-diisocyanate and 2 moles of allyl alcohol. The reaction I was continued with stirring at 60 C for 2 hours. Thereafter a borates, phosphates, diatomaceous earth, talc, kaolin, barium sulfate, calcium sulfate, calcium carbonate, antimony oxide and the like. The aforesaid additives may be present in quantities up to SOD parts or more per 100 parts polymer by weight and preferably about 0.0005 to about 300 parts on the same basis.

The compounding of the components prior to curing may be carried out in several ways. For example, the polyene, the polythiol and any other additives may be admixed and charged to an aerosol can, drum, tube, or cartridge for subsequent use.

Another useful method of compounding is to prepare in an ambient atmosphere by conventional mixing techniques but in the absence of actinic radiation a composition consisting of polyene, antioxidant (to inhibit spontaneous oxygen-initiated curing), polythiol, UV sensitizer or photoinitiator, and other inert additives. This composition may be stored in the dark for extended periods of time, but on exposure to actinic radiation (e.g., ultraviolet light, sunlight, etc.) will cure controllably and in a very short time period to solid polythioether products.

The mole ratio of ene/thiol groups for preparing the curable composition is from about 0.2/1 to about 5/1, and desirably about 0.75/1 to about 1.5/1 group ratio.

The following examples will aid in explaining, but should not be deemed as limiting, the instant invention. In all cases, unless otherwise noted, all parts and percentages are by weight.

vacuum of 1 mm. was applied for 2 hours at 60 C to remove the excess alcohol. This CH CH terminated prepolymer had a molecular weight of approximately 1950 and will hereinafter be referred to as Prepolymer C.

EXAMPLE 4 1 mole of a commercially available poly(propylene ether) glycol having a molecular weight of about 1958 and a hydroxyl number of 57.6 was charged to a resin kettle equipped with a condenser, stirrer, thermometer and a gas inlet and outlet. 4 g. of dibutyl tin dilaurate as a catalyst was added to the kettle along with 348 g. (2.0 moles) of tolyene-2,4-diiso cyanate and l 16 g. (2 moles) of allyl alcohol. The reaction was carried out for 20 minutes at room temperature under nitrogen. Excess alcohol was stripped from the reaction kettle by vacuum over a 1 hour period. The thus formed CH CH- terminated liquid prepolymer had a molecular weight of approximately 2400 and will hereinafter be referred to as Prepolymer D.

EXAMPLE 5 750 g. of a N-containing tetrol (hydroxyl functionality 4 available from Wyandotte Chemicals Corp. under the tradename Tetronic Polyol 904 having a M.W. of 7,500 was placed in a reaction vessel heated at 110 C. The flask was maintained under vacuum for 1 hour. Then, under an atmosphere of nitrogen, 0.1 cc. dibutyl tin dilaurate was added and the flask was cooled to 50 C. Now 18.3 g. allyl isocyanate was added slowly, maintaining the temperature at about C for about 1 hour after the addition was completed. The thus formed polymeric polyene (i.e., Prepolymer E hereinafter) had a theoretical allyl functionality of 2.2, a theoretical hydroxyl functionality of 1.8, and a calculated molecular weight of about 7,683.

EXAMPLE 6 To a resin kettle maintained under a nitrogen atmosphere and equipped with a condenser, stirrer, thermometer and gas inlet and outlet was added 843 g. of a commercially available liquid diisocyanate prepolymer sold under the tradename Multrathane F-196 by Mobay Chemical Co., said prepolymer having a molecular weight of about 1,680 and an available isocyanate content of 4.7 5.2 percent. 87 g. (1.5 moles) of allyl alcohol was added to the kettle and the reaction was continued for 18 hours at 140 C with stirring. Thereafter the nitrogen atmosphere was removed and the kettle was evacuated for 22 hours at 100 C. 50 cc. of dry benzene was added to the kettle and the reaction product was azeotroped therewith to remove any unreacted alcohol. This CH CH- terminated liquid prepolymer had a viscosity of 25,000 centipoises at 70 C and a molecular weight of approximately 1800 and will be referred to as Prepolymer F hereinafter.

EXAMPLE 7 678 g. (0.34 moles) of a commercially available poly(propylene ether) glycol sold under the tradename NIAX by Union Carbide Co. and having a molecular weight of about 2025 was degassed for 2 hours at 100 C and thereafter charged to a resin kettle maintained under a nitrogen atmosphere and equipped with a condenser, stirrer, thermometer and gas inlet and outlet. 118 g. (0.68 moles) of tolylene 2,4-diiso cyanate was charged to the kettle and the reaction was heated with stirring for 2 3/4 hours at 120 C. After cooling, 58 g. (1.0 moles) of allyl alcohol was added to the kettle and the mixture was refluxed at 120 C for 16 hours under nitrogen. Excess allyl alcohol was removed overnight by vacuum at 100 C. Half of the allyl terminated liquid prepolymer having a viscosity of 19,400 cps at 30 C as measured on a Brookfield Viscometer was removed from the kettle and will be referred to hereinafter as Prepolymer G. The other half portion of the prepolymer was combined with 50 cc. of dry benzene and azeotroped overnight following which excess benzene was pulled out under vacuum for 5 hours at 120 C. This portion of the allyl-terminated liquid prepolymer had a viscosity of 15,600 cps at 70 C as measured on a Brookfield Viscometer and a molecular weight of approximately 2,500 and will hereinafter be referred to as Prepolymer H.

EXAMPLE 8 751 g. (0.38 moles) of a commercially available poly(propylene ether) glycol sold under the tradename Pluracol P 2010" by Wyandotte Chemical Co. was degassed at room temperature for 3 hours and then charged to a dry resin kettle maintained under a nitrogen atmosphere and equipped with a condenser, stirrer, thermometer and gas inlet and outlet. 132 g. (0.76 moles) of tolylene-2,4-diisocyanate was charged to the kettle and the kettle was heated for 2 hours at 120 C with stirring under nitrogen. After cooling 58 g. (1.0 moles) of allyl alcohol was added and the mixture was refluxed at 20 C overnight. Excess allyl alcohol was stripped by vacuum overnight at 120 C. The thus formed allyl terminated liquid prepolymer had a viscosity of 15,000 cps as measured on a Brookfield Viscometer at 70 C and a molecular weight of approximately 2,500 and will hereinafter be referred to as Prepolymer I.

. EXAMPLE 9 ether)glyco1, commercially available from Quaker Oats Co. and having a hydroxyl number of 37.1 along with 0.3 g. dibutyl tin dilaurate. The temperature of the kettle was raised to C and the contents were freed of water under 1 millimeter vacuum for 1 hour. The resin kettle was cooled to 60 C and the system was placed under a protective atmosphere of nitrogen throughout the remainder of the reaction. 25.2 g. of allyl isocyanate, (0.4 mole) was added dropwise to the kettle at such a rate as to maintain the temperature at 60 C. When the NCO content dropped to 0.54 mg/g., 1 mm. vacuum again was applied and the system was heated at 70 C for 1 hour. The thus formed polymer product was a solid at room temperature but at 50 C is clear and pourable. The polymer product had a viscosity of 1,800 centipoises at 70 C as measured on a Brookfield Viscometer and an average molecular weight of approximately 3,200.

EXAMPLE 10 To a 1 liter resin kettle equipped with stirrer, thermometer, gas inlet and outlet was charged 591 g. (0.30 mole) of a poly(propylene ether) glycol commercially available from Union Carbide'under the tradename PPG 2025 and 0.3 g. of dibutyl tin dilaurate. The kettle was heated to 110 C and the contents were freed of water under 1 mm. vacuum for 1 hour. The kettle was cooled to 25 C and the system was placed under a protective atmosphere of nitrogen throughout the remainder of the reaction. 53.1 ml. (49.8 g., 0.6 mole) of allyl isocyanate commercially available from Chemetron Corp. was added to the system. An exotherm carried the temperature to 45 C in 22 minutes. After 60 minutes, the NCO content (as determined by titration) was 0.04 mg/g. The system was placed under 1 mm. vacuum and heated to 70 C to remove traces of unreacted allyl isocyanate. The resultant polymer product had a viscosity of 600 centipoises at 30 C as measured on a Brookfield Viscometer and an average molecular weight of approximately 2,200.

The next two examples show a method of preparing the polyenes of the instant invention by dehydration of polyether glycols.

EXAMPLE 1 l 100 g. of poly(propylene ether) glycol commercially available from Union Carbide under the tradename PPG 2025" was poured through a hot tube filled with aluminum oxide at such a rate that the entire reaction took place in 2 hours. The tube was 1 inch in diameter with the reaction zone 1 ft. long and completely enclosed within a tube furnace. The alumina catalyst was 10-18 mesh and was maintained at 350 C using a Lindberg Hevi-Duty tube furnace. The tube was fitted with a dropping funnel and a nitrogen inlet at the top. Nitrogen pressure was kept on the system throughout the reaction. The product collected from the bottom of the tube was analyzed for unsaturation by the mercuric acetate titration method and was found to have 100 percent of the theoretical amount of unsaturation expected after dehydration of both terminal hydroxyl groups of the poly(propylene ether) glycol. The polyene product had a viscosity of cps at 70 C and an average molecular weight of approximately 2,000.

EXAMPLE 12 l kilogram of poly(propylene ether) glycol commercially available from Union Carbide under the tradename PPG 2025" was heated to 120 C in a round bottom flask. To this was added 120 ml. (20 percent excess) of acetic anhydride at such a rate that the temperature of the mixture was kept at 120-140 C. Following the addition, the mixture was heated at C for 4 hours. It was then cooled and diluted with an equal volume of chloroform, washed with 10 percent aqueous sodium carbonate, then with water. The organic layer was separated and the chloroform was removed by distillation. Infrared analysis of the purified material showed it to be the diacetate of the poly(propylene ether) glycol with no residual hydroxyl groups. 1

100 g. of this diacetate was put through the hot tube as in Example 1 1 except that the packing was glass helices instead of alumina and the temperature was 375 C. The product contained 64 percent of the theoretical amount of unsaturation expected after the elimination of acetic acid from both terminal acetoxy groups of the poly(propylene ether) glycol diacetate.

EXAMPLE 13 114 g. of hexol sold under the tradename NIAX Polyol LS-490"by Union Carbide Chemicals Co. having a molecular weight of 684 was charged to a 1 liter 4 neck flask and heated to 110 C under vacuum and nitrogen for 1 hour. It was then cooled to approximately 60 C whereat 0.1 cc. of dibutyl tin dilaurate was added followed by slowly adding 83 g. (1 mole) of allyl isocyanate to keep the temperature in the range 70-80 C during the addition. After addition, the reaction was allowed to continue for 1 hour at 70 C. The polymeric hexaene product obtained had an average molecular weight of approximately 1,200 and a viscosity of 300 centipoises at 70 EXAMPLE 14 To a 1 liter 4 neck flask was charged 300 milliliters of dimethylformamide, 35 g. of tolylene-Z,4-diisocyanate and 0.1 cc. of dibutyl tin dilaurate. A mixture of 1 1.6 g. of allyl alcohol and 22.8 g. of hexol commercially available from Union Carbide Chemical Co. under the tradename NIAX Polyol Ls-490" having a molecular weight of 684 was slowly added to the flask. Temperature was kept at approximately 65 C during the addition and for a period of 1 hour. The polymeric product obtained had an average molecular weight of approxi mately 2,100.

EXAMPLE 15 To a 1 liter 4 neck flask wascharged 100 cc. of dimethylformamide, 100 g. of tolylene-2,4-diisocyanate and 0.1 cc. dibutyl tin dilaurate. 58 g. of hexol, i.e. NIAX Polyol Ls-490 by Union Carbide and 34 g. of allyl alcohol were mixed together and added dropwise to the flask. Before the addition to the flask was completed, the reaction, which was exothermic, gelled and the addition was discontinued.

A comparison of Examples 13, 14 and 15 shows that Example 13 is an improvement over Examples 14 and 15 in that it allows one to form polymer without the necessity of a solvent. A comparison of Examples 14 and 15 shows that when starting with a highly functional polyol using the diisocyanate/allyl alcohol technique one must operate in dilute solution to avoid premature crosslinking (i.e., gelation) which renders the polyene product useless as a curable liquid prepolymer. This problem is avoided completely by using the unsaturated monoisocyanate technique illustrated in Example 13.

EXAMPLE 16 In a 1 liter, 4 neck flask 220 g. of hexol commercially available from Union Carbide Chemicals Co. under the tradename NlAX Polyol LS-490" (0.32 moles) and 0.1 cc. of dibutyl tin dilaurate was heated to 1 10 C under vacuum for 1 hour. After cooling in nitrogen to approximately 60 C, 80 g. of allyl isocyanate was added to the flask by means of a dropping funnel. The exothermic reaction produced a temperature of 100 C. When the addition was complete the reaction was continued at 70 C for 1 hour. The resulting triene polymer product had an average molecular weight of approximately 950 and a viscosity of 300 centipoises as measured on a Brookfield Viscometer at 70 C.

EXAMPLE 17 To a 1 liter 4 neck flask was charged 300 g. of a polyester diol (molecular weight 3232) sold under the tradename "RC Polyester 7 S 101-35 by R. C. Division, Hooker Chemical Corp. and 0.1 cc. of dibutyl tin dilaurate. The flask was heated to 1 10 C of dibutyl tin dilaurate. The flask was heated to 1 10 C under vacuum and maintained thereat for 1 hour. The flask was cooled to approximately 60 C, nitrogen was admitted, and 7.7 g. allyl isocyanate and 8.1 g. of tolylene-2,4-diisocyanate was added by means of a dropping funnel to the reaction at a moderate rate. A maximum temperature of 90 C was needed. When the addition was complete the reaction was allowed to continue at 70 C for 1 hour. The thus formed solid polymeric product had an average molecular weight of approximately 6,800 anda viscosity of 13,600 centipoises when measured on a Brookfield Viscometer at 70 C.

EXAMPLE 18 To a 1 liter 4 neck flask heated at 110 70was charged 808 g. of a polyester diol (having a molecular weight 3232) sold under the tradename RC Polyester S 101-35" by R. C. Division Hooker Chemical Corp. and 0.1 cc. dibutyl tin dilaurate. The flask was maintained under vacuum at 110 C for 1 hour. The flask was cooled to approximately 50 C and with I nitrogen passing through, a mixture of 10 g. of allyl alcohol and 60 g. of tolylene-2,4-diisocyanate was added via a EXAMPLE 19 Following the procedure of Example 12 and using necessary reactants, a polyene of the following formula was prepared:

EXAMPLE 20 Following the procedure of Example 3, and using necessary reactants, a polyene of the following formula was prepared:

A crotyl-terminated polyurethane which contains two reactive double bonds per average molecule in a near terminal position was prepared following the general procedure of Example 3. The resulting polymeric polyene was found to have 25 the following formula:

EXAMPLE 23 55 Following the procedure of Example 3, and using necessary reactants, a polyene of the following formula was prepared:

No cure in hrs. in dark room.

' TABLE I Polyene: UV Example Polyono Polypolythiol acceler- Numhor prepolymer thiol 1 mole ratio UV accelerator ator (g.) Curing observations P-33 1:0. 66 None Cured to an odorless solid in 4 wks. Q43 1:0. 5 d Cured to an odorless solid in 1 wk. P-43 1:0;66 Acetone 0. 2 Cured to an odorless solid in 1 wk. Q43 1:0. 5 .do 0. 2 Cured to an odorless solid in 1 day. Q-43 1:0. 5 Mieitlyl ethyl 0. 2 Cured to an odorless solid in 4 days.

e one. Q43 1:0. 5 Acetophenone... 0. 5 Cured in 1 hr. Q-43 1:0. 5 Cyclohexanone 0. 5 Cured in 3 hrs. P-43 1:0. 5 Acetophenone. 0. 5 Cured in 1 hr. Q-43 1:0. 5 do 0 g Cured to an odorless solid in minutes.

EXAMPLE 59 1510 g. of a commercially available polyoxypropylene glycol sold under the tradename Pluracol P 2010 by Wyandotte Chemical Corp. was charged to a resin kettle maintained under a nitrogen atmosphere and equipped with a condenser, stirrer, thermometer and gas inlet and outlet. The reactant was degassed at room temperature for 3 hours. 265.4 g. of an 80-20 percent isomer mixtureof tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate respectively sold under the tradename .Mondur TD 80 was charged to the kettle and the kettle was heated for 2 hours at 120 C withi stirring under nitrogen. Thereafter, 116.9 g. (2 moles) of allyl alcohol was addedto the kettle and the mixture was refluxed for 16 hours at 120 C. Excess allyl alcohol was stripped by vacuum at 1 15 C for 23 hours. The thus-formed Cl-I,= CH- terminated polyene prepolymer had a molecular weight of approximately 2,460-2,500, and a viscosity of 16,000 cps as measured on a Brookfield viscometer at 30 C.

0.005 moles of the thus-formed polyene prepolymer were charged to a 2 02. glass jar along with a stoichiometric amount of the polymeric dithiol prepared in Example 65. 0.5 g. of

"acetophenone' (a UV photoinitiator) was charged to the glass jar and the mixture was immediately stirred. Thereafter the mixture was placed outdoors for UV curing. In 24 hours a solid, self-supporting, odorless, cured elastic polymer resulted.

EXAMPLE 60 EXAMPLE 61 Example 60 was repeated except that 0.02 moles of diallyl phthalate was substituted for the diallyl adipate. A self-supporting, solid, odorless, cured polythioether polymer product resulted in less than 1 hour.

EXAMPLE 62 2:

Example 60 was repeated except that 0.02 moles of diallyl succinate was substituted for the diallyl adipate. A self-supporting", solid, odorless, cured polythioether product resulted in 30 minutes.

EXAMPLE 63 Example 60 was repeated excep tthat 0.02 moles of 2,2-diallyloxypropane was substituted for the diallyl adipate. A selfsupporting, solid, odorless, cured .polythioether polymer product resulted in less than 1 hour.

etrakis (fl-mercaptopropionate).

EXAMPLE 64 polymer.

EXAMPLE 65 1.5 moles of Bmercaptopropionic acid, 0.5 moles of a commercially available poly(propylene ether) glycol sold under the tradename Pluracol P-20l0 by Wyandotte Chemical Corp. and 0.1 g. p-toluenesulfonic acid and 50 ml. benzene were charged to a resin kettle maintained under a nitrogen atmosphere and equipped with a condenser, stirrer, thermometer and gas inlet and outlet. Themixture was heated and the benzene-water azeotrope was collected. The actual amount of water collected amounted to 17.5 g. The reaction was vacuum-stripped for several hours at C to remove benzene. The resulting polythiol polymer had a molecular weight of about 2,2l0-2,230 and an average functionality of 2 and was collected for use herein.

659 g. (0.145 moles of a poly(propylene ether) triol commercially available from Wyandotte Chemical Corp. under the tradename Pluracol TPE 4542 having a molecular weight of about 4,500 and a hydroxyl number of 37.1, and 0.3 g. of dibutyl tin dilaurate were charged to a resin kettle maintained under a nitrogen atmosphere and equipped with a condenser, stirrer, thermometer and gas inlet and outlet. The reactants were maintained at 110 C for 1 hour and then cooled under nitrogen to room temperature. 25.2 g. (0.435 moles) of allyl alcohol was added to the kettle followed by 75.7 g. (0.435 moles) of an -20 percent isomer mixture of tolylene-2,4-diisocyanate and tolylene 2,6-diisocyanate respectively sold under the tradename Mondur TD 80. The temperature reached 55 C in 6.minutes. A sample was titrated for NCO resulting in 6.02 mg. NCO/g. after 20 minutes. After 1 hour the NCO titration showed 0.997 mg.

NCO/g. The polyene polymer had a molecular weight of about 5,200 and an average functionalityof 3 and was vacuum stripped at 70 C for 1 hour and then collected. 0.003 moles of the polythiol-polymeric material formed supra were charged to a 2 02. glass jar along with 0.002 moles of the allyl-terminated polyene polymer formed herein and 0.5 g. acetophenone. The reactants were'stirred briefly and then placed outdoors under atmospheric conditions. In one-half hour a self-supporting, solid, odorless, clear, cured polythioether polymer product resulted.

EXAMPLE 66 3 g. of a linear saturated hydrocarbon backbone ethylene/propylene/non-conjugated diene terpolymer commercially available under the tradename Nordel" by E. l. du- Pont de Nemours Co. which had been visbroken until it had a reduced specific viscosity of 0.99 and contained 0.4 vinyl, 6.4 trans and 0.4 vinylidene unsaturated groups per 1000 carbon atoms, was dissolved in 100 ml. of benzene in a glass jar. A 50 percent excess over the stoichiometric amount, i.e. 0.0006 moles (0.3 g.) of pentaerythritol tetrakis(/3-mercaptopropionate) was added to the jar in addition to 0.5 g. acetetophenone. The glass jar was placed in the sunlight outdoors under atmospheric conditions. After 24 hours the benzene had substantially evaporated leaving a gelatinous polymeric precipitate. Acetone was added to precipitate more polymer. The polymer was filtered off, washed with acetone and dried in a vacuum oven at 60 C.

2.3 g. of the above polythioether polymer product was extracted with benzene along with a control" sample of the starting visbroken Nordel material. The control sample showed a gel content (benzene insoluble) of 3.4 percent whereas the cured (crosslinked) solid polythioether polymer product had a gel content of 82.8 percent.

EXAMPLE 67 0.5 moles of a carboxyl-terminated polyisobutylene, commercially available from Enjay Chemical Co. having a molecular weight of about 1,800, 0.1 g. of p-toluenesulfonic acid catalyst), l.5 moles of allyl alcohol were charged to a resin kettle maintained under a nitrogen atmosphere and equipped with a condenser, stirrer, thermometer and gas inlet and outlet. The mixture was heated at reflux for 2 hours, then 50 ml.

benzene added and the benzene-water azeotrope was collected. The actual amount of water collected amounted to 17.5 g. The reaction was vacuum stripped for several hours at 70 C to remove benzene and any unreacted allyl alcohol.

0.005 moles of the thus formed polyene (9.6 g.), 0.0025 moles (1.2 g.) of pentaerythritol tetrakis(fi-mercaptopropionate) and 0.5 g. of aceptophenone were charged to a 2 oz. glass jar and briefly stirred. The jar was placed out-doors under ambient conditions. After one-half hours, a self-supporting, solid, odorless, cured elastomeric product resulted.

EXAMPLE 68 643 g. (0.32 moles) of a commercially available poly- (propylene ether) glycol sold under the tradename Pluracol P 2010" by Wyandotte Chemical Co. was degassed at room temperature for 1 hour and then charged to a resin kettle maintained under a nitrogen atmosphere and equipped with a condenser, stirrer, thermometer and gas inlet and outlet. 1 11.4 g. (0.64 moles) of a 80-20 percent isomer mixture of tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate respectively sold under the tradename Mondur TD 80 was added to the kettle. After 45 minutes, the temperature was raised to 120 C and the reaction was continued for 50 minutes. A sample was removed and titrated for NCO resulting in 33.54 mg. NCO/g. 62.7 g. of diallyl amine was added at 105 C and the reaction was continued for 10 minutes. A sample was titrated resulting in an NCO content of 1.20 milligrams NCO/g. A vacuum was applied to the kettle for 1 hour at 90 C followed by cooling under nitrogen. The resulting product had a molecular weight of about 2,5402,580 and an ene functionality of 4.

10 g. of the thus formed polymer was charged to a 2 oz. glass jar along with 2 g. of pentaerythritol tetrakis (B-mercaptopropionate and 0.5 g. acetophenone. The liquid reactants were briefly stirred togetherand placed out-doors under ambient conditions. Within 15 minutes a solid, odorless, elastomeric cured polythioether product was obtained.

EXAMPLE 69 with 41.5 g. allyl isocyanate was charged to a resin kettle maintained under a nitrogen atmosphere and equipped with a condenser, stirrer, thermometer and gas inlet and outlet. The reactants were maintained at 70 to C during addition. The reaction was continued for 1 hour at 70 C.

10 g. of the thus formed polymer were charged to a 2 02. glass jar along with 1.5 g. of pentaerythritol tetrakis (B-mercaptopropionate) and 0.5 g. of acetophenone. The mixture was briefly stirred and placed outdoors in the sun light at ambient conditions. Within 2 hours a solid, self-supporting, odorless, cured polymer product was formed.

The example was repeated using 180 g. of poly(ethylene imine) and 29.1 g. of allyl isocyanate under the same conditions and procedure. 10 g. of this polyene product was reacted with 2.1 g. of pentaerythritol tetrakis (B-mercaptopropionate) and 5 g. of acetophenone. The mixture was briefly stirred and placed outdoors in the sun light at ambient conditions. Within 2 hours a solid, self-supporting, odorless, cured polymer product was formed.

EXAMPLE 70 The polymeric polythiol (0.003 moles, f=2) from Example 65 was admixed with a stoichiometric amount (0.002 moles, F3) of a monomeric polyene, glycerol trioleate (triolein, molecular weight 885) and 0.5 g. acetophenone. The jar containing the reactants after mixing was placed in the sunlight under ambient conditions. Withinone-half hour the liquid mixture was converted to a self-supporting, solid, odorless, clear rubbery cured polythioether product.

The following example shows the operability of the instant invention when the polyene contains acetylenic linkages.

EXAMPLE 71 400 g. (0.20 moles) of a commercially available liquid polymeric diisocyanate sold under the tradename Adiprene 15-100 by E. 1. duPOnt de Nemours & Co. was charged to a dry resin kettle maintained under a nitrogen atmosphere and equipped with a condenser, stirrer, thermometer and gas inlet and outlet. 25.2 g. (0.45 moles) of propargyl alcohol was charged to the kettle and the reaction was continued for 17 hours with stirring at C. Thereafter the nitrogen atmosphere was removed and the kettle was evacuated 15 hours at 100 C. 10 g. of the propargyl terminated liquid prepolymer, 3.0 g. of pentaerythritol tetrakis (B-mercaptopropionate) and 0.5 g. acetophenone were admixed together in a 2 oz. glass jar, stirred briefly and placed outdoors under ambient conditions. Within 2 )6 hours a solid, odorless, self-supporting, cured elastomeric polymer product resulted.

EXAMPLE 72 40 g. of Prepolymer l and 10 g. of a filler sold commercially under the tradename Hi Sil 233 by Columbia Southern Chemical Corp. were charged under nitrogen to a 200 ml. round bottom 3 necked flask maintained under a nitrogen atmosphere and mixed thoroughly. The flask was heated by a water bath to 60 C under full vacuum for 2 hours. The flask was then allowed to cool under vacuum. 4 g. of pentaerythritol tetrakis (B-mercaptopropionate) was charged to the flask under nitrogen and the reaction was stirred continuously. The reaction was then exposed to ultraviolet light from the atmosphere outdoors and a solid, cured, odorless elastomeric product resulted within 15 minutes.

EXAMPLE 73 g. of Prepolymer E from Example 5 herein was charged to a Erlenmeyer flask equipped with a magnetic stirrer and connected by tubing to another Erlenmeyer flask containing 54 g. of trimethylolpropane tris (B-mercaptopropionate). The system was evacuated (0.05 mm.) while heating the polymer to 100 C with stirring. After 2 hours all bubbling ceased. An additional one-half hour evacuation was performed. Thereafter the trimethylolpropane tris( B-mercaptopropionate) was poured into the flask containing Prepolymer E under nitrogen. After stirring to insure good mixing, heat was removed and the reaction was continued under nitrogen for 4 days. No curing was observed. A sample of the unreacted material was removed from the Erlenmeyer flask under nitrogen and placed in a 2 oz. jar. The sample was EXAMPLE 81 The following fonnulations were made up:

exposed to ambient conditions outdoors and in about 2 5 lnsrediems 122? iauon i gfl i minutes evidence of curing (viscosity change) was observed. p p Within 15 minutes, an odorless, solid elastomeric, cured polymer product was obtained, under UV light. prepolymer D from Example 4 100 100 go, (pisgg lent) 4 4 EXAMPLE 74 10 uiiifi i 303 2 Thickening agent (75% silicia 4 4 10 g. of Prepolymer E from Example 5 was added to each of ii fi i g i z i s l 0 three 2 oz. jars. To one of the jars was added 3 ml. of benzene (mercapmpwpionme) containing 0.5 percent based on the weight of the prepolymer of an antioxidant sold under the tradename Santonox" commercially available from Monsanto Chemical Co. To another The above formulations were briefly admixed for of the jars containing Prepolymer E was added 3 ml. of homogeneity and thereafter air cured indoors. Formulation l benzene containing 0.5 percent based on the weight of th cured in approximately 6 hours to an elastomeric sealant prepolymcr f an i id d under h ud D lwhereas Formulation ll cured in 2 days to an elastomeric seapac F commercially available from Hercules Powder C lant. Curing was accomplished more rapidly when the samples To the third jar was added 3 ml. of benzene as a control. T0 were Placed Outdoors in Sunlight after mixingblend the components the jars were heated in a forced draft oven set at 150 C for minutes with frequent stirring. The EXAMPLE 82 jars were withdrawn from the oven and 1.3 g. of trimethylol- 25 propane tris (B-mercaptopropionate) was added to each of of Prepolymer D were charged to a 2 3 1 along the jars and curing was initiated indoors under ambient condig g 'zyg giz ggzgis a zsg l fz figag lryb tions. The control run, without any antioxidant present, cured genzo henone The reactants i g stir'red within one-half hour to a solid elastomeric polymer product. p between two pieces of glass p z each 3 5 m The ample comalmng Dalpac PG cured to a i 3o thickness. The glass plates were pressed together by hand to Rolymer ff Ffter 12 days whereas the Sample coniammg insure good adhesion, and then exposed to a Type RS Sunjgggigg; figg gfi zgs gg z xizfi gg a solid Selflamp at a surface radiation intensity of 4,000 microwatts/am' The 01 used in the instam invention ma be used as for 5 minutes. An attempt was made to pull the glass plates p y apart. The glass broke before the adhesive was destroyed. blends or mixtures of monoenes or polyenes havmg the same or different functionalities so long as the average functionality EXAMPLE 83 of the blend or mixture is at least 2. Similarly, the polythiols used herein may be used as blends or mixtures of monothiols 50 f prepolymer H along with f pemaerythmol Poiythlols having the or diflel'ent functltfnalitis as 40 tetrakis (mercaptopropionate), and 0.5 g. of benzophenone 8 as the average functionality of the blend at were stirred together briefly in a glass jar and then poured into least an aluminum mold in the shape of a shallow dish. The mold The Polyem/polythitll mole l'atio is select'fd to P was photocured by the procedure of Example 82 after which a solid final cured Product, w one that onflowing and the mold was torn away from the molded article which set to a structurally self-supporting under ambient conditions. In typi- Solid in a exact Shape f the mold cal cases, as shown by the examples, this ratio can be about 0.2 to 5 moles thiol groups per mole ene groups. In general the EXAMPLE 84 mole ratios significantly above or below. 1 'tend to give a high proportion of chain extension or grafting whereas mole ratios to i: f: 6 83; E sggi j z'gigzz f f near 1 give predominantly chain extension and crosslinlting. 5O P p i i fimercgptoprop'ionate) and o 5 g Y L; z zrg a t gigggiz f g j g fiix acetophenone. The reactants were stirred briefly and then w 2:: z gtsggtg fixiafi gg g figz outand ofiers no light. After l0 mins. a clear solid coating resulted on the The following Examples 75 8o Show the ability to use mi paper. The same technique was used successfully to coat celmrcs of the polythi 01s and how to empirically determine the lophane, aluminum foil, steel plate stock, Mylar" polyester amount of pol ythi o1 necessary to form cured solid self film, plywood, and a concrete block of the type used in buildporting polymeric products by the instant invention. mg construction As shown in Examples -80, 30 g. of Prepolymer I from EXAMPLE Example 8 were admixed with varying ratios of a mixture of polythiols and cured by ultraviolet light in the presence of 20 g. of the polymeric product from Example 9 was mixed acetophenone as a UV photoinitiator. with 2.2 g. of pentaerythn'tol tetrakis (B-mercaptopropionate) Polythiol mixture (g.) Aceto- Outdoor Curing Shore A Self- Example Polyene phenone curing time hardsupport Number polymer Q-43 E233 (g.) site (mins.) ness structure 2.9 O 0. 5 X 7 40 Yes. $32 8:? 9 3? $22: of e 2: 3 81? 5% 53, ii 0 2.9 0.5 X N0.

1 Polyene prepolymer I from Example 8.

2 Q43=pentaerythrit0l tetrakis (fl mercaptopropionate) commercially available from Carlisle Chemical Co.

3 EZ3=ethylene glycol bis (8 mercaptopropionate). 4 No cure.

commercially available from Carlisle Chemical 00. under the tradename Q43 and 0.5 g. of acetophenone in a 2 oz. aluminum tray, stirred briefly and cured by irradiating with ultraviolet light from a Sylvania Sun lamp. Within 4 minutes a solid, odorless, elastomeric product resulted.

EXAMPLE 90 10.6 g. of decaglycerol dioleate (Drew Chemical Corp.) and 2.0 g. of pentaerythritol tetrakis (B-mercaptopropionate) were dissolved in ethanol, 1.0 g. of acetophenone was ad- 5.5 g. of decaglycerol decaoleate (Drew Chemical Corp.) 7

mixed therewith and the mixture in an aluminum tray was EXAMPLE 86 tplaced1 outdoors in the sunlight. After 3 days a cured film was orme 20 g. of the polymeric product from Example 10 was mixed EXAMPLE 91 in an aluminum dish with 2.2 g. of pentaerythritol tetrakis (B- g g .33s-52331122155311;zizzi'giszrsissa; emica 0. un er e tra ename an g. o acetophenone. The mixture was irradiated for 3 minutes by ulwere admixed m an ethylenebenzene Soluuon an alummum traviolet light from a Sylvania Sun lamp. The sample cured to L0 9 of acemRhenme added to the mlxture andfthe a tack-free solid which had a color of less than 1 on the mlxmre was Placed the sunllght- After 3 y a cured Gardner Scale. After exposure in a Fadeometer for 47.2 resultedhours, the color increased to a value of 4 on the Gardner EXAMPLE 92 Scale.

A similar polymer prepared from PPG-2025," tolylene- 2,4-diisocyanate and ally] alcohol, cured with pentaerythritol and 8' ofethylene g y bis (fip p p tetrakis (fl-mercaptopropionate) and acetophenone by irmercially available from Carlisle Chemical Co. under the radiation with ultraviolet light also had a Gardner color of less ll'adename El-23 were dissolved in an ethanol-benzene soluthan 1. However, after 47.2 hours in the Fadeometer the tion in an aluminum tray. 1.0 g. of acetophenone was added to Gardner color rose to 13. the mixture and the mixture was placed in the sun. After 3 25 days a semi-solid cured film resulted. EXAMPLE 87 EXAMPLE 93 f E d 5 2252;322:23 :2 3: 2 53 3232,5 15; 5.2 g. of decaglycerol dioleate (Drew Chemical Corp.) and were admixed 810 g with 0.4 acetophenone in a beaker A 2.0 g. of ethylene glycol bis (fi-mercaptopropionate) were disfilm approximately 0035 inch thick (45 inch Square) was solved in ethanol in an aluminum tray. 1.0g. ofacetophenone spread on a glass plate and cured by irradiating it for 5 minutes :1: :332 g fi t gf gland m the with ultraviolet light from a Westinghouse sun lamp 8 to 10 link d 8 pro a not 1 to a cross inches above the film. The resultant cured product had a tene ne wot sile strength of 368 psi and an elongation at failure of 27 ei- EXAMPLE 4 cent Its Shore A hardness was 80 to 94.5 g. of dimer acid commercially available from Emery Industries Inc. under the tradename Empol 1010 and 103.5 EXAMPLE 88 g. of allyl alcohol were admixed in benzene in a 2 neck flask. 10 g of the polymer product from Example 18 was melted The reaction was heated gently for 19 hours at 80 C at which and of Solvent (equal volumes of toluene and 2 ethoxy 40 time it was determined by titration that less than 6 percent of ethyl acetate) was added to lower the viscosity of the melt. To gi scgzg frg itg i z ltglr z t gz igssgig fiiig Y2: this solution was added 0.35 g. of pentaerythritol tetrakis (B5- thus formed emulsion was Salted out thoroughly the ber'lzene mercaptopropionate). The solution was mixed and a 0.03 inch sheet was cast and irradiated for 30 minutes with a lig Separate; zfi q to remove 'f molsPure' Westinghouse sun lamp. The resultant, clear, cured product i j e o m vacuum to o tam the diallyl crystallized slowly to a white opaque material which had a tengfi 23 of the dimer acid mduct was admixed sile strength of 6,310 psi and an elongation at failure of 720 withuoJy, in a 1'] mole ratio and l acetophenone in an percent It had ashore A hardness ofover aluminum tray and cured in the sun. After 2 hours a cured solid product resulted. EXAMPLE 89 The curing example was repeated except that the mole ratio I of the diallyl ester of dimer acid to Q-43" was 2:1. The cured 6 8- of g y moleme (Armour Industrial chemlcfil product was harder than the product obtained under the 1:1 and 2.4 g. of pentaerythritol tetrakis (B-mercapto-propronate) ole ratio ofdiallyl ester to Q-43.

were dissolved in an ethanol-benzene solution and placed in an aluminum tray. 1.0 g. of acetophenone was added and admixed and the mixture was exposed to the ultraviolet rays of the sun for 3 days. A cured solid film was formed in 3 days.

14 g. of dimer acid, 6 g. of pentaerythritol tetrakis (fl-mercaptopropionate) and 1.0 g. of acetophenone were mixed in an aluminum tray. The mixture was placed in the sun. After 22 hours the product had not solidified to a crosslinked network.

EXAMPLES 95-117 UV thru cure Shore A Sample Photocuring** rate Polyrate hardness,

Number Polyene Source of Polyene accelerator thicl" mils/min. UV cured 1,2,4-trivinylcyclohexane.- Aldrich Chem. 09., Inc Benz0phen0nc 23.3 70

. 1,5-hexadienc Aldrich Chem. 00., Inc .do. 35.0

. Diallyl terephthalat Chemicals Procurement Lab. Inc 21.0 60

.. Diallyl oxalate. Monomer-Polymer Labs, Inc. 5.0 80

10..-. Diallyl l,4-cyclol1exane-dicarboxylate.. Monomer-Polymer Labs., Inc-. 3.0

100 Tetruullyl ortllosilicate Aldrich Chem. 00., Inc ..d0 Q43 8.8 60

101 Dinllyl diphenylsilane Chemicals Procurement Lab. Inc do....-..... 43.7

102........ Dinllyl allyl phospllonatc Aldrich Chem. 00., Inc ..do.... 17. 5 {)0 103 Diullyl phonyl pl1ospl1ite...- K. & K. Laboratories, Inc .-d0. 11.7 70

104 N,N-dinllyll'ormmnidt Aldrich Chem. 00., Inc ..do... 7.0 50 105.. N.N,N,N-t tranllylrnetliylenc- Monomer-Polymer Labs, Inc ..d0 Q-43 4.4 75- (limninv.

106. Trinllylcymnn-nto Aldrich Chemical 00 Dibcnzosuberonc........ P-33 7.0 35

107.. 4-vinyl-l-cyclohoxmiu K. (I: K. Laboratories, Inc Benzophenone Q43 1.6 70

108 (l)ivtllylcnt glycol divinyl ether (.0 Iolyscienccs, Inc Dibenzosul)cronc........ Q-43 36.6 42

EXAMPLES 95-117 Continued UV thru cure" Shore A bnmple Photocurmw" rate Polyrate hardness, Number Polycnc Source of Polyene acceleratorthiol" mils/min. UV cured 1)iallyl amine (.1 mole). Monomer-Polymer Labs, Inc 109 'Iriallyl phosphate Aldrich Chemical (30., lnc 10.0 20 110 Diallyl carbonate. Chemical lroc. Labs, inc. 125. 03 111.. N,N-diallyl pipcra Chemical lroc. Labs, Inc. 25." 57 112 Allyl diglycol carbotmt Cit-3i) from lltl ind. Inc 100.0 6: 113 Polymeric dieue Example .i 5 20 do do ()Ch (15 parts/100 (.1-43 6 10 plus phenimthrene. 115 do ..do o-Methoxyphenyl- (.1-43 10 20 methyl ketone. 116 do do o-Mcthoxybcnz- Q43 10 20 aldehyde. 117 ..do.; .d0 C014 parts/100) Q-43 3 Q-43 is pentaerythritol tetrakis (B-mercaptopropionate); P-33 is trimethylolpropanc tris (B-mercaptopropionate). The. polythiol is used in the theoretical equivalent amount based on the polyenc used.

"Sample thickness ranged from 35 to 140 mils; UV source was a 275 watt Type RS sun lamp; incident radiation intensity at surface of photocurable composition was 4000 microwatts/cmfl.

"Concentration of photocuring rate acceleratonvaried from 0.2 to 1.5 parts/100 parts photocurablc composition.

EXAMPLE 1 l8 916 g. (0.46 moles) of a commercially available liquid polymeric diisocyanate sold under the tradename "Adiprene L400" by E. l. duPont de Nemours and Co. was charged to a dry flask maintained under a nitrogen atmosphere and equipped with a condenser, stirrer, thermometer and gas inlet and outlet. 197 g. (0.92 moles) of the diallyl ether of trimethylolpropane was charged to the vessel along with 0.56 g. dibutyltin dilaurate catalyst. The flask and contents were heated with stirring for 30 minutes at 50 C. to yield a polytetraene of about 2,400 M.W.

To the tetraene was added 230 g. pentaerythritol tetrakis (fl-mercaptopropionate), 18.4 g. benzophenone, 1.2 g. dilaurylthio-dipropionate, 136 grams of dioctyl phthalate, and 1.2 g Plastanox 2246 (hindered phenol antioxidant sold by American Cyanamid Co.). This photocurable liquid composition was cast on a glass plate in a layer 40 mils thick. It was then exposed to UV radiation from a 275 Watt Type RS sunlamp. The intensity of the radiation incident on the surface of the layer was 3000 microwatts/cm. The layer skin cured in about l-2 seconds and cured to a solid through the entire thickness in less than 20 seconds, or at a liquid-to-solid conversion rate of over 120 mils/minute. The solid rubbery product had a Shore A hardness of 72, a tensile strength of 150 psi and an alongation at failure of 40 percent.

The solid cured polythioether polymer products resulting from the instant invention have many and varied uses. Examples of some uses include but are not limited to adhesives; caulks; elastomeric sealants; coatings, encapsulating or potting compounds; liquid castable elastomers; thermoset resins; impregn'ants for fabric, cloth, fibrous webs and other porous substrates; laminating adhesives and coatings; mastics; glazing compounds; fiberglass reinforced composites; sizing or surface finishing agents, filleting compounds; cure in place gasketing compounds; rocket fuel binders; foamable thermosetting resins or elastomers; molded articles such as gaskets, diaphragms, balloons, automobile tires, etc.

The molecular weight of the polyenes of the present invention may be measured by various conventional methods, including solution viscosity, osmotic pressure and gel permeation chromatography. Additionally, the molecular weight may be calculated from the known molecular weight of the reactants.

The viscosity of the polyenes and polythiols may be measured on a Brookfield viscometer at 30 or 70 C in accord with the instructions therefor.

The components to be cured may be prepared as either single-packaged or multi-packaged liquid polymer systems which may be cured to solid polythioether elastomers without liberating gaseous by-products which cause bubbles and voids in the vulcanizate. Thus, there is provided curable liquid polymer systems composed of polyenes and polythiols in which the components individually are storage stable and which are not sensitive to or deteriorated by traces of moisture or oxygen containing gas such as may be encountered during normal storage or handling procedures. Solid'resinous or elastomeric products may be prepared from flowable liquid in a system in which the rate of curing may be inhibited or retarded by the use of chemical inhibitors, antioxidants, inert atmospheres and the like. The cured product may be characterized as in the thermally and oxidatively stable state since there is no reactive carbon-to-carbon unsaturation in the main backbone chain.

As used herein the term polyene and the term polyne refers to single or complex species of alkenes or alkynes having a multiplicity of terminal reactive carbon-to-carbon unsaturated functional groups per average molecule. For example, a diene is a polyene that has two reactive carbon-to-carbon double bonds per average molecule, while a diyne is a polyyne that contains in its structure two reactive carbon-to-carbon triple bonds per average molecule. Combinations of reactive double bonds and reactive triple bonds within the same molecule are also possible such as for monovinylacetylene which is a polyeneyne under this definition. For purposes of brevity all these classes of compounds are referred to hereafter as polyenes.

In defining the position of the reactive functional carbon-tocarbon unsaturatiomthe term terminal is intended to mean that functional unsaturation is at an end of the main chain in the molecule; whereas by near terminal is intended to mean that the functional unsaturation is not more than 10 carbon atoms and typically less than eight carbon atoms from an end of the main chain in the molecule. The term pendant means that the reactive 'carbon-to-carbon unsaturation is located terminal or near-terminal in a branch of the main chain as contrasted to a position at or near the ends of the main chain. For purposes of brevity all of these positions are referred to hereingenerally as terminal unsaturation.

Functionality as used herein refers to the average number of ene or thiol groups per molecule in the polyene or polythiol, respectively. For example a triene is a polyene with an average of three reactive carbon-to-carbon unsaturated groups per molecule and thus has a functionality (f) of three. A dithiol is a polythiol with an average of two thiol groups per molecule and thus has a functionality (f) of two.

It is to be understood that the functionality of the polyene and the polythiol component is commonly expressed in whole numbers although in practice the actual functionalitymay be fractional. For example, a polyene component having a nominal functionality of 2 (from theoretical considerations alone) may in fact have an effective functionality of somewhat less than 2. In an attempted-synthesis of a diene from a glycol in which the reaction proceeds to 100 percent of the theoretical value for complete reaction, the functionality (assuming 100 percent pure starting materials) would be 2.0. If however, the reaction were carried to only percent of theory for complete reaction, about 10 percent of the molecules present would have only one one functional group, and there may be a trace of material that would have no one functional groups at all. Approximately 90 percent of the molecules, however,

37 38 would have the desired diene structure and the product as a k havi f on t i a b atoms d id whole then would have an actual functionality of 1.9. Such a cycloalkyl having from three to eight carbon atoms; product is useful in the instant invention and is referred to h i [A] i f e f reactive b .mb unsatw herein as having a functionality of ration; free of highly water-sensitive members; and is a The term reactive unsaturated carbon-to-carbon groups 5 polyvalent chamicauy ibl member fth group means groups which will react under P p l conditlons as Set consisting of carbonate, carboxylate, carbonyl, ether, forth herein with thiol groups to yield the thioether linkage Silane, silicate, phosphonate phosphite phosphate,

I alkyl and substituted alkyl, cycloalkyl and substituted s cycloalkyl, aryl and substituted aryl, urethane and subl 0 stituted urethane, urea and substituted urea, amine and as contrasted to the term unreactive carbon-to-carbon unsaturation which means groups found in aromatic nucleii (cyclic structures exemplified by benzene, pyridine, anthracene, and the like) which do not under the same conditions react with thiols to give thioether linkages. 20

substituted amine, amide and substituted amide, hydroxyl, heterocyclic carbon containing radical, and mixtures thereof; said substituents on said members being defined above, said component having a molecular weight in the range from about 64 to 20,000; and a viscosity in the range from essentially 0 to million centipoises at 70 C.; B. a polythiol component having a molecular weight in the range from about 50 to about 20,000 of the general formula:

Highly water-sensitive groups are intended to include, for R8 example, isocyanate, acylhalide such as acylchloride, anhydride and the like which readily react with water, alcohols, ammonia, amines and the like.

Odorless has been used herein to mean the substantial absence of the well-known offensive and sometimes obnoxious odors that are characteristic of hydrogen sulfide and the derivative family of compounds known as mercaptans.

The term non-yellowing means the substantial resistance wherein R is a polyvalent organic moiety free from reactive carbon-to-carbon unsaturation and n is at least 2, the sum of m and n being greater than 4, with the ene/thiol mole ratio being selected so as to provide a cross-linked solid, selfsupporting cured product; and

C. a photocuring rate accelerator.

2. The composition of claim 1 wherein [A] has the formula:

during prolonged exposure to actinic radiation such as expo- II sure in sunlight, to unsightly or uncontrollable discoloration.

It is understood that the foregoing detailed description is given merely by way of illustration and that many variations 3 a 4 b may be made therein without departing from the spirit of this invention.

What is claimed is:

1. A photocurable composition useful for obtaining an essentially odorless, solid polythioether, said photocurable composition consisting essentially of:

A. a terminally unsaturated polyene component which comwherein a and b are integers greater than 1 R is a member of the group consisting of hydrogen and alkyl; R is a member of the group consisting of hydrogen, and

saturated alkyl; R, is a divalent derivative of the group consisting of phenyl, benzyl, alkyl, cycloalkyl, substituted phenyl, substituted [AH X)m benzyl, substituted alkyl and substituted cycloalkyl,

said alkyl, cycloalkyl and substituents on members substituted being defined in claim 1.

prises the formula:

wherein m is an integer of at least 2, wherein X is R R R 3. The composition of claim 5 wherein the photocuring rate l accelerator is a member selected from the group consisting of L aryl aldehyde, diaryl ketone, alkyl aryl ketone, triaryl phos- R f phine, and a blend of carbon tetrahalide with polynuclear aromatic hydrocarbon. where f is an integer from 1 to 9; R is a radical selected 4. The composition of claim 1 wherein the polyene has the from the group consisting of hydrogen, fluorine, formula:

(UJHZ n chlorine, furyl, thienyl, pyridyl, phenyl and substituted wherein n is at least 1; and

phenyl, benzyl and substituted benzyl, alkyl and sub- R is a member of the group consisting of stituted alkyl, alkoxy and substituted alkoxy, cycloalkyl f and substituted cycloalkyl; said substituents on said CH2 T C1127? substituted members selected from the group consisthydrogen, phenyl, cycloalkyl and alkyl;

ing of nitro, chloro, fluoro, acetoxy, acetamide, phenyl, said substituent on member which is substituted, the cycloalbenzyl, alkyl, alkoxy and cycloalkyl; said alkyl and alkyl, and the alkyl defined as in claim 1. 

2. The composition of claim 1 wherein (A) has the formula: wherein a and b are integers greater than 1; R2 is a member of the group consisting of hydrogen and alkyl; R3 is a member of the group consisting of hydrogen, and saturated alkyl; R4 is a divalent derivative of the group consisting of phenyl, benzyl, alkyl, cycloalkyl, substituted phenyl, substituted benzyl, substituted alkyl and substituted cycloalkyl, said alkyl, cycloalkyl and substituents on members substituted being defined in claim
 1. 3. The composition of claim 5 wherein the photocuring rate accelerator is a member selected from the group consisting of aryl aldehyde, diaryl ketone, alkyl aryl ketone, triaryl phosphine, and a blend of carbon tetrahalide with polynuclear aromatic hydrocarbon.
 4. The composition of claim 1 wherein the polyene has the formula: wherein n is at least 1; and R7 is a member of the group consisting of CH2=CH CH2n , n, hydrogen, phenyl, cycloalkyl and alkyl; said substituent on member which is substituted, the cycloalkyl, and the alkyl defined as in claim
 1. 5. The composition of claim 1 wherein the polyene has the formula:
 6. The composition of claim 1 wherein the polyene has the formula:
 7. The composition of claim 1 wherein the polyene has the formula:
 8. The composition of claim 1 wherein the polyene has the formula:
 9. The composition of claim 1 wherein the polyene has the formula:
 10. The composition of claim 1 wherein the polyene has the formula:
 11. The composition of claim 1 wherein the polyene has the formula:
 12. The composition of claim 1 wherein the polyene has the formula:
 13. The composition of claim 1 wherein the polyene has the formula: where n is at least
 1. 14. The composition of claim 1 wherein the polyene has the formula:
 15. The composition of claim 1 wherein the polyene has the formula: wherein the sum of x + y + z is at least 1; n is at least 1; and R7 is a member of the group consisting of CH2=CH CH2n , hydrogen, alkyl, phenyl, and cycloalkyl said alkyl and cycloalkyl defined as in claim
 1. 16. The composition of claim 1 wherein the polyene has the formula: wherein the sum of x + y + z in each chain segment is at least 1; n is at least 1; R1 is selected from the group consisting of hydrogen, phenyl, benzyl, alkyl, cycloalkyl, and substituted phenyl; and R7 is a member of the group consisting of CH2=CH CH2n , =, hydrogen, alkyl, phenyl, and cycloalkyl; said member which is substituted, the cycloalkyl and the alkyl defined as in claim
 1. 17. The composition of claim 1 wherein the polyene has the formula: wherein the sum of x + y + z in each chain segment is at least 1; n is at least 1; R7 is a member of the group consisting of CH2=CH CH2n , hydrogen, phenyl, cycloalkyl and alkyl; said member which is substituted, the cycloalkyl and the alkyl defined as in claim
 1. 18. The composition of claim 1 wherein the polyene has the formula:
 19. The composition of claim 1 wherein the polyene has the formula: C3H5-O C3H6-O C3H5 wherein y is at least
 1. 20. The composition of claim 1 wherein the mole ratio of ene to thiol is from about 0.2/1 to about 5/1.
 21. The composition of claim 1 wherein the mole ratio of ene to thiol is about 0.75/1 to about 1.5/1.
 22. A process of forming essentially odorless solid polythioether which comprises I. Admixing: A. a terminally unsaturated polyene component which comprises the formula: (A= X)m wherein m is an integer of at least 2; wherein X is where f is an integer from 1 to 9; R is a radical selected from the group consisting of hydrogen, fluorine, chlorine, furyl, thienyl, pyridyl, phenyl and substituted phenyl, benzyl and substituted benzyl, alkyl and substituted alkyl, alkoxy and substituted alkoxy, cycloalkyl and substituted cycloalkyl; said substituents on said substituted members selected from the group consisting of nitro, chloro, fluoro, acetoxy, acetamide, phenyl, benzyl, alkyl, alkoxy and cycloalkyl; said alkyl and alkoxy having from one to nine carbon atoms and said cycloalkyl having from three to eight carbon atoms; wherein (A) is free of reactive carbon-to-carbon unsaturation; free of highly water-sensitive members; and is a polyvalent chamically compatible member of the group consisting of carbonate, carboxylate, carbonyl, ether, silane, silicate, phosphonate, phosphite, phosphate, alkyl and substituted alkyl, cycloalkyl and substitute cycloalkyl, aryl and substituted aryl, urethane and substituted urethane, urea and substituted urea, amine and substituted amine, amide and substituted amide, hydroxyl, heterocyclic carbon containing radical, and mixtures thereof; said substitutents on said members being defined above, said component having a molecular weight in the range from about 64 to 20,000; and a viscosity in the range from essentially 0 to 20 million centipoises at 70* C.; B. a polythiol component having a molecular weight in the range from about 50 to about 20,000 of the general formula: R8=SH)n wherein R8 is a polyvalent organic moiety free from reactive carbon-to-carbon unsaturation and n is at least 2, the sum of m and n being greater than 4, with the ene/thiol mole ratio being selected so as to provide a cross-linked solid, self-supporting cured product; and C. a photocuring rate accelerator, and thereafter II. exposing the mixture to actinic light.
 23. A photocurable composition useful for obtaining an essentially odorless, solid polythioether, said photocurable composition consisting essentially of: A. a terminally unsaturated polyene component having the formula:
 24. The solid product prepared by the process of claim
 23. 25. The process of claim 23 wherein the actinic light is ultraviolet radiation having a wavelength between about 2,000 A and about 4,000 A.
 26. The process of claim 23 wherein the composition contains from 0.0005 to 50 parts by weight of a photocuring rate accelerator.
 27. The process of claim 23 wherein the photocuring rate accelerator is selected from the group consisting of aryl aldehyde; diaryl ketone; alkyl aryl ketone; triaryl phosphine; a blend of carbon tetrahalide with polynuclear aromatic hydrocarbon.
 28. An article comprising the composition of claim 23 as a coating on a substrate.
 29. An article comprising the composition of claim 23 as an adhesive between two substrates.
 30. An article comprising the composition of claim 23 as an elastomeric sealant.
 31. A shaped, molded article cast from the composition of claim
 23. 